[alsa-devel] [PATCH V1 2/3] ASoC: fsl_spdif: spba clk is needed by spdif device

[Nicolin Chen]

On Wed, Nov 04, 2015 at 04:34:44PM +0800, Shengjiu Wang wrote:
> I discussed this issue with IC team. The SPBA bus has 3 master port,
> one is for SDMA, one is for MCU (ARM core), the third one is for DSP (
> currently there is no connection for DSP). Any two master port are used
> simultaneously, there will be arbitration issue when SPBA clock is not
> enabled.
> 
> So I think it is better put SPBA clock in Audio IP, because if there is
> DSP master port + MCU master used, there will be issue too. (DSP master 
> port is not used in i.MX chip). Anyway I think put it in SDMA driver is
> not good choice, if SDMA is removed, there will be still issue. Put it
> in Audio IP maybe more safe.

It's really ambiguous here as it's not easy to say which side is
the best. I'm personally okay if you insist so. However, you need
to refine the patch as I suggested in my first reply and document
it well: Apparently, "dma" is not a good name for this clock. And
it should be an optional property so as not to break the old DTBs.
And only the platforms (check DT compatible) that use the arbiter
can fetch the clock or get a warning when not present in the DTB.

Thanks
Nicolin